1. Field of the Invention
This invention relates to a disc cassette and to a loading device for positioning the disc cassette on a recording and/or reproducing apparatus.
2. Description of the Prior Art
It has been proposed, for example, in my copending U.S. patent application Ser. No. 06/383,208 filed May 28, 1982, and having a common assignee herewith, to provide a disc cassette or cartridge in which a so-called "floppy" disc or diskette is housed within a substantially flat jacket which protects the disc from crumpling, folding or other damage, particularly when the magnetic disc cassette is not in use or when it is being transported. In order to permit a magnetic transducer to gain access to the disc for recording or reproducing signals thereon without requiring the removal of the magnetic disc from the jacket, the jacket is provided with a window through which the transducer of a magnetic recording and/or reproducing apparatus can effect magnetic contact with a surface of the disc when the jacket is operatively positioned in the apparatus. In order to avoid the entry of dust or damaging contact with the magnetic disc through the window, the earilier proposed jacket is provided with a shutter movable between opened and closed positions in respect to the window. Usually, a spring is provided within the jacket for urging the shutter to its closed position, and the recording and/or reproducing apparatus intended for use with such disc cassette includes a cassette holder in which the jacket is slidable during its insertion and removal to and from an operative position, with a projection being provided in the cassette holder for moving the shutter to its opened position against the force of the spring acting thereon in response to the slidable insertion of the jacket to its operative position.
The earlier proposed disc cassette has also been provided with a latch within the jacket for holding the shutter in its closed position, and such latch is automatically released by the projection which thereafter acts on the shutter for moving the latter to its opened position in response to the insertion of the jacket to its operative position. On the other hand, when the jacket is slidably withdrawn or removed from the cassette holder, the spring acting on the shutter moves the latter to its closed position where it is again locked or secured by the latch.
However, it has been found that the assembling within the jacket of the spring for urging the shutter to its closed position is a troublesome and relatively costly operation, and further that the spring is prone to failure due to fatigue after repeated use of the cassette. If such spring does fail, or if the spring is omitted from the disc cassette assembly, the shutter is not automatically moved to its closed position in response to the withdrawl or removal of the jacket from the cassette holder. In that case, the shutter may remain open after removal of the jacket from the holder, thereby giving rise to the possibility of damage to the magnetic disc through the opened window. Further, it is troublesome to close the shutter by manual operation thereof after removal of the jacket from the cassette holder.